The role of the biostatistics core is to support the investigators of this leukemia grant in their research efforts, including laboratory experiments, and the design and analysis of clinical trials. In preclinical studies, core members will assist in the formulation of the experimental design and in the analysis and interpretation of the data at the conclusion of the study. In the clinical trial design phase, a core member will assist the principal investigator in the development of a clinical protocol. At the conclusion of the clinical trial, data analyses will be performed to assess outcomes of the primary and secondary endpoints stated in the protocol. In addition, retrospective data analyses will be performed to address specific clinical research questions. If the current statistical methodology does not adequately address a research question in this grant, alternative methodologies will be explored. . The specific aims of the Biostatistics Core are to: 1. contribute to the design and analysis of the laboratory studies; 2. contribute to the design and analysis of the clinical studies; - 3. develop statistical methodology that will assist in the advancement of leukemia cancer research. Relevance: The Biostatistics Core is essential to the design, ongoing review and final analysis of preclinical experiments and clinical trials to translate biological questions into experimentally testable hypotheses yielding interpretable results and to insure that planned clinical trials are feasible, invoke appropriate design and stopping rules to insure safety and are appropriately analyzed and interpreted.